The study, which was also presented during the 2014 American College of Cardiology Scientific Sessions in Washington DC, also found that strictly applying the reduced blood pressure goal would be considered to have achieved the targeted blood pressure for their age groups, researchers from the Duke University Medical Center in Durham, North Carolina said in a statement Saturday.

According to the paper’s authors, this is the first peer-reviewed analysis to examine the impact of the revised guidelines announced last month by the Eighth Joint National Committee. As part of their recommendations, the committee lowered the blood pressure goal for those over the age of 60 from 140/90 to 150/90, and also reduced target BP levels for US adults diagnosed with diabetes and kidney disease.

“Raising the target in older adults is controversial, and not all experts agree with this new recommendation,” explained Ann Marie Navar-Boggan, lead author of the study and a cardiology fellow at the Duke University School of Medicine. “In this study, we wanted to determine the number of adults affected by these changes.”

The Duke investigators, along with colleagues from McGill University in Montreal, used data collected between 2005 and 2010 as part of the US Centers for Disease Control and Prevention (CDC) National Health and Nutrition Examination Survey (NHANES). Based on a sample of 16,000 people, the authors determined that the proportion of American adults eligible for hypertension would fall from 40.6 percent to 31.7 percent under the new guidelines.

Furthermore, they estimated the proportion of younger adults (those between the ages of 18 and 59) considered to have treatment-eligible high blood pressure would fall from 20.3 percent under the old guidelines to 19.2 percent under the new ones. For men and women 60 years of age or older, the percentage would fall from 68.9 percent to 61.2 percent. Overall, 5.8 million adults would no longer be classified as needing hypertension medication.

“Public health messaging should target the large number of adults in the United States with changing recommendations under new guideline to ensure that new recommendations do not result in unintended consequences in adults now with ‘relabeled’ BP status,” the authors wrote, adding that additional research was needed to determine the impact of the new guidelines on overall blood pressure levels.

“The new guidelines do not address whether these adults should still be considered as having hypertension. But they would no longer need medication to lower their blood pressure,” added Navar-Boggan. “These adults would be eligible for less intensive blood pressure medication under the new guidelines, particularly if they were experiencing side effects. But many experts fear that increasing blood pressure levels in these adults could be harmful.”